This application is based on and incorporates herein by reference Japanese Patent Application No. 2002-9895 filed on Jan. 18, 2002.
The present invention relates to a starter in which a pinion gear moves on an output shaft with a one-way clutch and engages with a ring gear of an engine.
A starter of related art that is disclosed in JP-U-64-39475 includes a one-way clutch and an electromagnetic switch. The one-way clutch is connected with an output shaft via a helical spline. The electromagnetic switch performs on and off control of a current supply to a motor. The one-way clutch is pushed forward with a pinion gear by a lever that is driven by an attraction force of the electromagnetic switch. When the engine is started, the one-way clutch is pushed in the axial direction of the starter toward the rear due to counterforce of return springs included in the switch. Then, the one-way clutch is brought into contact with a washer fixed to the output shaft and stopped.
Since the washer, which functions as a stopper to stop the movement of the clutch, is fixed to the output shaft, a thrust force is applied to the output shaft. The force also affects a bearing at which a rear end of the output shaft is supported. Therefore, the bearing needs to be strong enough to tolerate the force. Such a bearing becomes large in the axial direction, and the starter having the bearing becomes large in the axial direction.
Additionally, a motor of the starter coasts for a while after power supply to the motor is stopped. If restarting the starter by mistake during this period, an impact on the pinion gear and the ring gear is larger than when restarting the starter from a standstill. Therefore, the gears become damaged when starting the starter while the starter is coasting.
The present invention therefore has an objective to provide a starter, a one-way clutch of which is attracted on the output shaft without being affected by thrust force, and a motor which is stopped immediately after power supply to the motor is stopped. In a starter of the present invention, a pinion gear of a starter engages with a ring gear of an engine by pushing a one-way clutch in the direction away from the motor via a lever. The lever is driven by an attraction force of an electromagnetic switch. The starter includes a braking member. The braking member applies a braking force to the one-way clutch by being placed it against the one-way clutch or a case, which causes friction, when the clutch is attracted toward the motor via the lever.
With this configuration, the rotation of the one-way clutch is stopped by the braking member immediately after the power supply to the motor is stopped by the electromagnetic switch. As a result, the coasting of an armature stops in a short time. This reduces damages to the gears if that the starter is restarted by mistake immediately after the starter is stopped. The damage can be reduced because the impact is reduced by the braking member when the pinion gear hits the ring gear.
When the one-way clutch is attracted by the lever, the one-way clutch is stopped by the case via the braking member and the thrust force is absorbed by the case. That is, large thrust forces are not applied to the output shaft and the rotor shaft of the motor (armature shaft). Therefore, the size of the bearing can be reduced in the axial direction, and the length of the starter can be reduced.